Cloud authenticated offline file sharing

Abstract

Described embodiments provide systems and methods for transferring a file. A sender device configured to transfer a file to a receiver device may send an identifier of the receiver device and a public key to a server via a first network. The sender device may receive, via the first network prior to disconnecting from the first network, a session token from the server. The session token and the public key may be sent to the receiver device via the first network. The sender device may detect, after receiving the session token, a peer-to-peer (P2P) wireless network established by the receiver device. The P2P wireless network may broadcast a service set identifier (SSID) with a network key encrypted using the public key. The sender device may connect, using the network key, to the P2P wireless network to transfer the file to the receiver device via the P2P wireless network.

What is claimed is: 
     
       1. A method for receiving a file at a receiver device, the method comprising:
 receiving, by the receiver device and from a server device, a public key and a session token, wherein the public key corresponds to a sender device; 
 encrypting, via the public key, a network key, wherein the network key comprises cryptographic information for establishing communications with the sender device; 
 broadcasting, by the receiver device, broadcast information indicating a peer-to-peer (P2P) wireless network established by the receiver device, wherein the broadcast information comprises a service set identifier (SSID) and the encrypted network key; and 
 receiving, via the P2P wireless network and from the sender device, the file. 
 
     
     
       2. The method of  claim 1 , further comprising:
 appending, by the receiver device and prior to broadcasting, the encrypted network key to the SSID. 
 
     
     
       3. The method of  claim 1 , further comprising:
 based on receiving, from the sender device and via the P2P wireless network, a copy of the session token, authenticating the sender device. 
 
     
     
       4. The method of  claim 3 , wherein the receiving a session token comprises receiving the session token from the server device responsive to the receiver device being authenticated with the server device. 
     
     
       5. The method of  claim 3 , further comprising disconnecting, by the receiver device and based on receiving the session token, from a first network connecting the server device and the receiver device. 
     
     
       6. The method of  claim 1 , further comprising authenticating, by the receiver device with the sender device, prior to the receiving the file. 
     
     
       7. The method of  claim 1 , further comprising terminating the P2P wireless network based on receiving the file from the sender device. 
     
     
       8. A system comprising:
 a server device configured to perform:
 receiving, from a sender device, a public key of the sender device; and 
 sending, to a receiver device, the public key; and 
 
 the receiver device, wherein the receiver device is configured to perform:
 receiving, from the server device, the public key; 
 encrypting, via the public key, a network key, wherein the network key comprises cryptographic information for establishing communications with the sender device; 
 broadcasting broadcast information indicating a peer-to-peer (P2P) wireless network established by the receiver device, wherein the broadcast information comprises a service set identifier (SSID) and the encrypted network key; and 
 
 receiving, via the P2P wireless network and from the sender device, a file. 
 
     
     
       9. The system of  claim 8 , wherein the server device is further configured to perform:
 prior to sending the public key, authenticating, based on an identifier received from the sender device, the receiver device. 
 
     
     
       10. The system of  claim 8 , wherein the receiving device is further configured to perform:
 appending, by the receiver device and prior to broadcasting, the encrypted network key to the SSID. 
 
     
     
       11. The system of  claim 8 , wherein the receiving device is further configured to perform:
 receiving, from the server device, a session token; and 
 based on receiving, from the sender device and via the P2P wireless network, a copy of the session token, authenticating the sender device. 
 
     
     
       12. The system of  claim 11 , wherein the receiving a session token comprises receiving the session token from the server device responsive to the receiver device being authenticated with the server device. 
     
     
       13. The system of  claim 11 , wherein the receiving device is further configured to perform disconnecting, based on receiving the session token, from a first network connecting the server device and the receiver device. 
     
     
       14. The system of  claim 8 , wherein the receiving device is further configured to perform authenticating, by the receiver device with the sender device, prior to the receiving the file. 
     
     
       15. The system of  claim 8 , wherein the receiving device is further configured to perform terminating the P2P wireless network based on receiving the file from the sender device. 
     
     
       16. The system of  claim 8 , wherein the P2P wireless network comprises a Wi-Fi Direct network. 
     
     
       17. A method comprising:
 receiving, by a server device and from a sender device configured to transfer a file to a receiver device, an identifier of the receiver device and a public key of the sender device; 
 sending, to the sender device, a session token, wherein the session token is configured to uniquely identify communications between the sender device and the receiver device in an ad-hoc network; 
 sending, to the receiver device and based on the identifier, the session token and the public key; and 
 based on sending the session token to the sender device and the receiver device, disconnecting from the sender device and the receiver device. 
 
     
     
       18. The method of  claim 17 , further comprising:
 authenticating the receiver device prior to sending the session token and the public key to the receiver device. 
 
     
     
       19. The method of  claim 18 , wherein the authenticating the receiver device comprises comparing the identifier received from the sender device with a second identifier received from the receiver device. 
     
     
       20. The method of  claim 17 , further comprising receiving, from the sender device, a message indicating that the sender device will disconnect from a network used to send the public key.